The purpose of percutaneous transluminal coronary angioplasty is to open a coronary artery which has become partially blocked by a stenotic lesion. A stenotic lesion is an abnormal narrowing of an artery due to injury or disease.
The procedure involves the introduction of a catheter system into the heart, by way of the femoral artery, under local anesthesia. The catheter system includes a guiding catheter and a dilating catheter. The end of the guiding catheter is inserted into the opening of the coronary artery.
The dilating catheter is passed through the guiding catheter into the coronary artery. The tip of the dilating catheter is passed through the stenotic lesion in the coronary artery. A balloon on the tip of the dilating catheter is then inflated with a fluid. The balloon forces the blockage open and enlarges the lumen, or passage, through the artery.
A problem sometimes develops with this technique, when the dilating catheter has to pass through a tight stenosis or blockage. The reactionary force on the catheter assembly may cause the guiding catheter to slip out of the coronary opening. This results in an unstable condition, and makes it much more difficult to pass the dilating catheter through the stenotic lesion.
The catheter assembly of the invention overcomes this problem by providing an inflatable balloon near the tip of the guiding catheter. After the guiding catheter has been inserted into the opening of the coronary artery, the balloon is inflated. The balloon engages the inner surface of the coronary artery, and stabilizes the guiding catheter. The dilating catheter is then passed through the guiding catheter and through the stenotic lesion, without forcing the guiding catheter out of the coronary lumen.
Side holes in the guiding catheter allow blood to bypass the inflated balloon on the guiding catheter. Otherwise, the inflated balloon would obstruct the flow of blood to the coronary artery.